Assessment of voltage stability for real-time operation

A voltage stability assessment method is developed that can identify i) voltage stability proximity ii) critical instability area, with a more useful voltage stability index-maximum instability angle presented here, a fuzzy logic considers the voltage stability index provided here and reactive reserve of the generators. Furthermore, attempt has been made to identify the critical instability area by C-means fuzzy clustering according to bus instability angel and voltage magnitude. This method is implemented for IEEE 39 bus system and can be sufficiently used for the real-time voltage stability assessment